DACHNOWSKI: BOG VEGETATION AND PEAT SOILS 57 
between 40 and 260 parts of total solids. The osmotic pressure and 
the acidity of the soil solutions differ but slightly between the 
various grades of peat soil. 
3. Reducing processes in peat soils, judged by methylene blue 
or a one per cent starch-iodid solution, increase from any marginal 
point of a peat-depositing lake to the bog meadow association and 
decrease as the deciduous forest association is approached. 
4. The nature of the changes which have taken place in the 
transformation of vegetable debris into peat is only partly under- 
stood. The principal changes are a relative loss in oxygen and 
hydrogen and a progressive increase in carbon and nitrogen. This 
is clearly shown in passing from the fibrous peat substratum of bog 
meadows to the structureless peat occupied by bog forests and 
deciduous trees. : 
5. In poorly decomposed peat the percentage of volatile 
combustible material is high, the percentage of fixed carbon, of 
nitrogen and ash is low. In well decayed peat the reverse is true. 
6. The higher ash content in peat from bog shrub and bog 
forest associations is believed to be due largely to windblown silt; 
a bog meadow association interferes less with wind work than the 
timbered area of a deposit.* 
7. Peat contains potash and phosphoric acid in comparatively 
inconsiderable quantities, only a fraction of one per cent, whereas 
the percentage of calcium and nitrogen is very high, varying from 
one to almost four per cent. The capabilities of a soil for crop 
production are usually judged from the study of the chemical 
character of the soil, and soils markedly deficient in phosphates, 
potash, and other salts, are looked upon as barren and sterile. 
Maintenance of fertility is connected with abundance of these 
constituents. In peat soils, it seems, the essential mineral salts 
of the agricultural tripod play only minor réles for protoplasmic 
activities and in the growth and ripening of bog plants. 
8. More systematic investigations from the standpoint of 
agricultural chemistry have shown that the number of possible 
inorganic nitrogenous substances, the quantity of nitrites, nitrates, 
and ammonia is quite small, ranging from a few thousandths to a 
few hundredths of one per cent. Practically all the nitrogen con- 
tained is, therefore, of organic nature. 
* Beyer, S. W. Peat deposits in Iowa. Iowa Geol. Sur. 19: 698. 1908. 
